[Brainmap]: Samuel Patz - Mapping Neural Circuitry and Brain Activity at High Speed (10Hz) using functional Magnetic Resonance Elastography (fMRE)

Samuel Patz, PhD

Associate Research Associate, Brigham and Women's Hospital

Professor of Radiology, Harvard Medical School

Abstract:

Using MR elastography, the shear modulus of mouse brains was monitored during noxious stimulation. Localized changes in tissue elasticity of >10% were observed in brain regions associated with noxious stimuli. The observed mechanical response persists over two decades of stimulus frequencies from 0.1-10 Hz. This demonstrates that the mechanism behind stiffness changes is not of vascular origin, which has a much slower response than 10Hz, but rather is either directly related to, or tightly coupled to primary neuronal activity. Accordingly, functional MR elastography (fMRE) may open a new window to explore the spatio-temporal processing of signals in the brain.

About the Speaker:

I’m a physicist working to develop new MRI methods. Currently, I’m doing research in three areas:

1. Hyperpolarized gas MRI to produce maps of pulmonary function including ventilation, gas exchange and perfusion. The subject inhales xenon gas that we have previously magnetized with a laser. We detect the signal both in the gas phase to provide maps of ventilation and in tissue and blood to measure gas exchange and perfusion.
2.  Development of a lightweight, portable MR device for the ICU. We are developing this to assist clinicians in setting optimal ventilator pressures for patients who are on assisted mechanical ventilation. By measuring the regional response of lung density to changes in ventilator pressures, one can minimize lung collapse or over distension and thereby reduce the very high mortality rate from ventilator induced lung injury. We are also working on a version of this device to detect cerebral perfusion in the neurosurgical ICU.
3. Magnetic Resonance Elastography (MRE) of the brain. MRE is a technique that allows one to produce spatial maps of tissue elasticity and viscosity. We are developing this method for the brain and examining its ability to (i) detect and stage gliomas and (ii) diagnose and stage Alzheimer’s disease because of the anticipated change in mechanical properties with deposition of amyloid plaque and/or tau protein.